Process for separating phosphoric acid from natural phosphates.



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MAXIMILIAN MATTHEUS HAFF, 0F

THOMAS LEOPOLD WILDSON, 0F

OTTAWA, ONTARIO, CANADA, ASSIGNOR TO DTTAWA, CANADA.

il,'7 8,4l97.-

No Drawing.

To all whom it may concern Be it known that l, MAXIMILTAN Mirr- THnUs Hart, a subject of thcKing of Great Britain, residing at the city of Ottawa, in the Province of Ontario, Canada, have invented certain new and useful Improvements in Processes for Separating Phosphoric Acid from Natural Phosphates, of which the following is a specification.

This invention relates to an improved process for separating phosphoric acid and the objects are to produce phosphoric acid by a process which 'will involve the handling of a minimum amount of material and may be carried out at sutliciently low cost to be commercially practicable.

The" invention comprises subjecting pulverized natural phosphates with clay to electric heat, and recovering the prosphoric acid as hereinafter set forth and described.

In practising the invention any well known natural phosphate, such as calcium phosphate or aluminum phosphate is pulverized and mixed with clay and brought to a molten state in a suitable electric furnace, preferably of the arc resistance type, and maintained in such molten state by the action of the electric are upon it, the temperature of the are usually being considered to be around 3000 centigrade.

The clay used' may be ordinary blue clay, and the proportion of it preferably as follows: parts clay, 100 parts phosphate. These proportions apply where the clay contains from sixty to seventy per cent. of silica,

fifteen to thirty-five percent. of alumina and naught to eight per cent. of iron oxid,

and the phosphate contains eighty-five per cent. of Ca (PO 'With other clays the proportions will be varied to correspond.

The slag is tapped out as it accumulates and the volatile phosphoric acid is caught in any suitable way, such as by a Water spray, or by moistened calcareous material such as raw crushed phosphate rockor lime. If de sired the phosphoric acid can be readily extracted from the vapors as a salt, by bring .ing ammonia, potash or soda into contact n Specification of Letters Patent.

Patented @ct. 21,1913.

Application filed April 4, 1912. Serial No. 688,544.

With these vapors and thereby fixing the phosphoric acid in commercial form. As an alternative, the vaporous acid might be first caught in water and then fixed by adding this solution to calcareous material or to the ammonia, soda or potash.

It may be noted that no reducing action whatever is depended upon, and it is preferable to prevent as far as possible the introreducing action on the phosphoric acid.

It may bestated that the present process is not intended to include within its range the use of feldspar or similar feldspathic aluminum silicate. The term clay is usedherein to indicate compounds, such as earth or soil, which generally pass under this name and are somewhat of the nature of aluminous silicates.

'What I claim as my invention is:

ing phosphoric acid which, comprises subjecting natural phosphate with a non-feldspathic aluminum silicate to the heat of the electric are under such conditions as to volatilize phosphoric acid, and recovering the volatilized phosphoric acid.

2. The herein described process of obtaining phosphoric acid, which comprises subjecting natural phosphate with a non-feldspathic aluminum silicate to the heat of. the electric are under such conditions as to volatilize phosphoric acid, and fixing the phos phoric acid With raw phosphate material.

3. The herein described process of obtaining phosphoric acid, which comprises subjecting sixty parts of a non-feldspathic aluminum silicate and one hundred parts of natural phosphate to the heat of the elec- .tric are under such conditions as to volatilize phosphoric acid, and recovering the volatile phosphoric acid.

In witness whereof I have hereunto set my handin the presence of two Witnesses.

MAXIMILIAN MATTHEUS HAFF.

Witnesses:

RUSSEL S. SMART,

Pnannn M. GARRow.

duction of any substance which will have a 1. The herein described process of obtain- 

